The world particle-physics community has convened in Vienna for the 2015 European Physical Society Conference on High Energy Physics (EPS-HEP2015), where the latest results in the field are being presented and discussed. ...

A century ago, Switzerland decided to electrify its railways. Out went coal, coal pollution and energy dependency. Today, what about switching all our cars over to electricity? The air would be cleaner, but what would be ...

Thousands of solar panels glint in the sun, but the prized farmland beneath lies barren. While the Italian island of Sardinia revels in a renewable energy boom, the long arm of organised crime risks sullying its clean power ...

The development of affordable and efficient ceramic fuel cells that could be used to power homes, the culmination of five years worth of work by Colorado School of Mines researchers, is featured in the July 23 issue of Science ...

EU's grid connected cumulative capacity in 2014 reached 129 GW, meeting 8% of European electricity demand, equivalent to the combined annual consumption of Belgium, the Netherlands, Greece and Ireland. According to a JRC ...

Ben-Gurion University of the Negev (BGU) and University of Western Australia researchers have developed a new process to develop few-layer graphene for use in energy storage and other material applications that is faster, ...

Energy

In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working") is a scalar physical quantity that describes the amount of work that can be performed by a force, an attribute of objects and systems that is subject to a conservation law. Different forms of energy include kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy. The forms of energy are often named after a related force.

Any form of energy can be transformed into another form, but the total energy always remains the same. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.

Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but non-zero kinetic energy relative to the Earth.